I think the answer might be as simple as this: you may have engaged the "Auto-Set Locators" option. Click-HOLD the cycle button int eh Transport to see if the top option is checked. If so, select it again to toggle it OFF. (It has a key command associated with it, which is how it may have accidentally been turned ON).You know, in the flow of recording I use all three.
There's not one culprit.